PRELIMINARY DESCRIPTIONS OF SOME JAPANESE TRICLADS. 



159 



Locality : — Lake Biwa, on muddy bottom at a depth of 30-45 fathoms. 

 Collected by Dr. N. Annandale and Mr. T. Kawamura, Oct. 191 5. 



5. Btlellocephala brunnea, n. sp. 



Woodcuts 9 — 11. 



Body moderately large, rather slender. Head indistinctly marked off 

 from trunk by a gentle neck-like narrowing of body. Frontal margin 

 crenate ; median lobe weakly arched, thrown into some adhesive folds on 



the inferiorly turned 

 swollen edge (wood- 

 cut 10) ; behind that 

 edge a groove-like 

 depression present ; 

 lateral lobes but little 

 projecting. Breadth 

 of frontal margin in the 

 creeping state of the 

 worm, less than half 

 the greatest breadth 

 of trunk. Trunk dor- 

 sally convex, ventral- 

 iy flat, very gradually 

 broadening posterior- 

 ly from neck to about 

 the region of sexual organs ; posterior extremity of body rather rounded. 



Body in the creeping state commonly 20-26 mm. long and 3-4 mm. 

 broad ; ratio of breadth and length I : 5-6^. 



Color of body olive-brown, sometimes blackish, velvety; the parts 

 containing guts usually darker than elsewhere. 



Eyes two, each surrounded by a white space ; distance between them 

 about twice as long as that between either of them and the nearest point in 

 the front margin or that in the lateral head margin. 



